Some communication systems allow the user of a device, such as a personal computer, to communicate across a packet-based computer network such as the Internet. Such communication systems include voice over internet protocol (“VoIP”) systems. These systems are beneficial to the user as they are often of significantly lower cost than conventional fixed line or mobile networks. This may particularly be the case for long-distance communication. To use a VoIP system, the user installs and executes client software on their device. The client software provides the VoIP connections as well as other functions such as registration and authentication. In addition to voice communication, the client may also provide other communication media such as video calling, instant messaging (“IM”), SMS messaging, file transfer and voicemail.
One type of communication system for packet-based communication uses a peer-to-peer (“P2P”) topology. To enable access to a peer-to-peer system, a user must execute P2P client software provided by a P2P software provider on their computer, and register with the P2P system to obtain a digital certificate. Calls or other communications can subsequently be set up and routed between users of the P2P system without the further use of a server in the set-up. Instead, the client looks up the IP addresses from information distributed amongst the P2P client software on other end users' computers within the P2P system, and the caller's P2P client software then exchanges certificates with the callee's P2P client software.
VoIP or other packet-based communications can also be implemented using non-P2P systems that do use centralized call set-up and/or authorisation, e.g. via server. In this case the client installed and executed on the user's computer is an application that accesses a server so that call signalling can be handled by the server. In certain situations a server based architecture may be increasingly desirable over a P2P topology.
Whatever architecture or topology is used, there is an increasing demand to integrate such packet-based communication systems into other partner communication systems or “partner platforms”, for example to integrate a VoIP system into a social networking site. However, although the user may only see this as a new user-interface for accessing the VoIP communications or such like, there are in fact a number of technical challenges involved in adapting the underlying system architecture to accommodate the partnership. One such challenge is ensuring an adequate degree of privacy when the user-bases of the two systems are to be merged. Generally speaking, privacy within a packet-based communication can be a concern in other situations as well.